To help reduce the cost of installation of home swimming pools and whirlpool spas, the use of plastic plumbing has become widely adopted. This in turn has given rise to the need for valves constructed of plastic materials, particularly valves which can act both as shutoff valves and as valves for directing water through various outlets from the pump. Three-way and four-way ball-type valves have heretofore been provided made of plastic materials. However, such known valves have required machining to close tolerances, and inner seals to prevent leakage. Moreover, known ball valves have provided restrictive flow passages through the valve.